Rand Paul wants to make sure that President Barack Obama won’t strike Syria if a congressional resolution authorizing the president to do so fails.

The Kentucky GOP senator is filing an amendment to the Senate’s proposed authorization of military force in Syria aimed at limiting Obama’s power if the effort to rally sagging congressional support falls short. Paul’s amendment is one of the first proposed to the resolution.

“Notwithstanding any other provision of law, the authority to use force resides in Congress, and the President does not have authority to carry out the military action set forth in this resolution absent passage of the resolution,” the amendment reads in entirety.

Paul has been one of the White House’s stiffest opponents of Obama’s proposed strike at Syrian President Bashar Assad, distributing a Dear Colleague letter on Monday warning the Obama has not effectively made the case for an attack.